Project Summary: This dissertation will specify properties of an event-related cortical potential labeled the Voice Related Cortical Potential (VRCP) as an index of neural preparation for voicing in a voice disordered population. A unique experimental design & methodological advances permit precise characterization of the VRCP. Subjects will breathe out of their nose or produce "mmm" (equivalent actions in terms of involvement of the articulatory tract, the only difference being the initiation of laryngeal movement when humming). Online co-registration of physiological measurements (i.e. measurement of voice onset using electroglottography and expiration onset using a tele-thermometer) with simultaneously-sampled brain data is made possible by innovative hardware adaptations. Electroencephalography (EEG) will be utilized for specification of time course, field distribution, & waveform morphology of the VRCP. Functional Magnetic Resonance Imaging (fMRI) will be used for anatomical specification of sources of the VRCP. The study will compare anatomical, topographical, & temporal properties of the VRCP in a voice-disordered population, & aim to test the hypothesis that adults presenting with a voice disorder secondary to Parkinson's Disease (PD), may show significant differences in: (a) the degree of activation of relevant brain sites; &/or (b) the timing/sequencing of activations when compared to age-matched control subjects. Correlations will be investigated between VRCP parameters & acoustic & perceptual indices. Post-intervention changes in this population, comparing people who have and have not been treated with the Lee Silverman Voice Treatment program (LSVT), an efficacious intervention for neurogenic voice disorder, will also be investigated. Long- Term Objectives:Training will facilitate the applicant's ability to: 1. conduct and disseminate research that is scientifically excellent & relevant to the concerns of disabled individuals, service providers, & the scientific community; 2. measure temporal and spatial characteristics of the VRCP. Relevance: Brain activation changes may be a factor in voice disorders of neurogenic origin; therefore, the findings have potential as a method for assessing cortical adaptation to clinical, medicinal, & surgical intervention for voice disorders. Voice disorders occur in an estimated 3-9% of the US population, and are undoubtedly a source of substantial functional loss for individuals, and economic cost to society. The studies contribute to the mission of the NIH & the fulfilment of Healthy People 2010 by providing valuable information about the neural mechanisms for voice production in a voice disordered population, & ultimately developing ecologically valid methods for evaluating and ameliorating the disability associated with voice disorder. [unreadable] [unreadable] [unreadable]